Many of us here are lucky to own TSC but also play TSW. I wouldn't be surprised if, given the recent core update to TSC and the research work that goes into making routes for both sims, we could see a simultaneous release of a new route for TSW3 and an updated one for TSC. With that in mind, which TSC route would you like to see either updated or backdated at the same time as it's release on TSW3. I'm always going to go for GEML in either in its 1989 guise but would settle for 2022. I think only North Somerset/Edinburgh/BML/MML are already in official TSC releases.
West Cornwall Local, Northern Transpennine, SEHS (in it's TSW2 form, minus the extensions), Great Western Express and Glossop Line all feature in TSC, but do so in very different forms.
Also the Northern Transpennine which is called TSC Huddersfield Line. On the TSC version a separate purchase is needed for Class 802 and 185. For the German routes you are looking at extended Nahverkehr Dresden Leipzig Hbf & Ruhr Sieg Strecke to Siegen which is left out.